Tunable multiline distributed feedback dye laser based on the phenomenon of excitation energy transfer

Tunable multiline distributed feedback (DFB) lasing has been observed in the mixture of dyes rhodamine 6G (R6G) and cresyl violet (CV). The dye-pair is pumped by the two pairs of the pump beams derived from a common source at two different angles. A variation in DFB geometry up to seven orders suggests that the third order Bragg diffraction is suitable for such studies. A detailed study at high dye concentrations has been done by steady-state and ps time-resolved spectroscopy. The energy transfer phenomenon and the self-absorption mechanism both, are found to be responsible for the observed tunability and multiline lasing. The threshold energies required for the DFB lasing are also given here.